+extern void get_current_sigmask(sigset_t *sigset);
+
+/* Set all deferrable signals into *s. */
+extern void sigaddset_deferrable(sigset_t *s);
+/* Set all blockable signals into *s. */
+extern void sigaddset_blockable(sigset_t *s);
+/* Set all gc signals into *s. */
+extern void sigaddset_gc(sigset_t *s);
+
+extern sigset_t deferrable_sigset;
+extern sigset_t blockable_sigset;
+extern sigset_t gc_sigset;
+
+extern boolean deferrables_blocked_p(sigset_t *sigset);
+extern boolean blockables_blocked_p(sigset_t *sigset);
+extern boolean gc_signals_blocked_p(sigset_t *sigset);
+
+extern void check_deferrables_blocked_or_lose(sigset_t *sigset);
+extern void check_blockables_blocked_or_lose(sigset_t *sigset);
+extern void check_gc_signals_blocked_or_lose(sigset_t *sigset);
+
+extern void check_deferrables_unblocked_or_lose(sigset_t *sigset);
+extern void check_blockables_unblocked_or_lose(sigset_t *sigset);
+extern void check_gc_signals_unblocked_or_lose(sigset_t *sigset);
+
+extern void block_deferrable_signals(sigset_t *where, sigset_t *old);
+extern void block_blockable_signals(sigset_t *where, sigset_t *old);
+extern void block_gc_signals(sigset_t *where, sigset_t *old);
+
+extern void unblock_deferrable_signals(sigset_t *where, sigset_t *old);
+extern void unblock_blockable_signals(sigset_t *where, sigset_t *old);
+extern void unblock_gc_signals(sigset_t *where, sigset_t *old);
+
+extern void maybe_save_gc_mask_and_block_deferrables(sigset_t *sigset);
+